Continental Drift: A Revolutionary Theory That Was Once Considered Pseudoscience

Continental Drift: A Revolutionary Theory That Was Once Considered Pseudoscience

2021-02-19 00:49:00

Scientific opinion is shifting in the same way as continents – very, very slowly. Sometimes change takes so long that the author of a new theory is no longer alive to see his work justified. Sometimes he freezes over on an expedition in an Arctic wasteland, decades before his peers finally recognize him as a visionary.

Such was the fate of Alfred Wegener (1880-1930), a German scientist who lived and died with the unshakable belief that the ground on which we stand is not as solid as it seems. He was right, of course. Geologists today accept the basis of his theory of continental drift – albeit in the more sophisticated context of plate tectonics – as a fact of nature: our planet's configuration of land and ocean was different millions of years ago and will be different millions of years. now.

However, experts at Wegener's own time dismissed the theory as pseudoscience and diagnosed it with "moving crust disease and wandering arctic plague." They eventually joined him on the right side of history, after half a century of efforts to discredit his work and belittle his character. But while he waited for the rest of the world to embrace his ideas, it had felt very well as if he were standing on the Florida coast, looking out to the horizon at the approach of Africa.

An outside perspective

The man who toppled the edifice of geological knowledge was not even a geologist. A trained astronomer, yes; a daring and renowned explorer, yes; an authority on earth sciences, no. Wegener was a meteorologist, better known for setting the world record for the longest flight in a hot air balloon rather than rock-related research.

(Source: Public Domain / Wikimedia Commons)

No doubt his lack of credentials put him at odds with established academics from the start, but their disdain also stemmed from the firm belief that the continents had always been in more or less the same position. Many people had made the blatant observation that the continents fit together like puzzle pieces (most clearly along the coasts of South America and Africa), but the dogma of continental sustainability ran so deep that Wegener was the first to seriously consider the logical conclusion: in a distant time they must have joined.

When he first noticed this puzzle competition in a world atlas, around Christmas 1910, he too thought it "unlikely," he wrote. But the following fall, he discovered that many fossils on both sides of the Atlantic Ocean, in West Africa and Brazil, were nearly identical. He also learned that to explain this, his contemporaries suggested that plants and animals crossed ancient land bridges that had since sunk into the oceans. Wegener began to think his hypothesis might not be improbable.

Read more: Plate Tectonics: The Slow Dance of Our Planet & # 39; s Crust

In the months that followed, as he built his business, he had no qualms about dropping the status quo. A month before publicly presenting his theory, in December 1912, he wrote to his mentor and future father-in-law, Wladimir Koppen: If the evidence favored the continental drift, he asked: "Why should we hesitate to change the old views?" to throw overboard? ? Why should this idea be held back for ten or even thirty years? "

In retrospect, it is clear that these are the words of an idealist. Unfavorable objectivity is the stated goal of science, it is true – but the response to Wegener's proposal strongly reminds us that flesh and blood scientists don't always check their emotions at the door of the laboratory.

The puzzle comes together

After publishing his first articles on the subject – which were largely ignored – in 1912, Wegener dropped his geological research for a while. He took part in an expedition to Greenland, returned and married Else Koppen, had a first child, Hilde, and was drafted into active service in Belgium at the beginning of the First World War.

Later, as he recovered from blows, he formulated his ideas in a book, The origin of continents and oceans, published in 1915. The premise was that the Earth's crust consisted of two layers, with the top layer constantly floating along the bottom, like the icebergs he had seen floating over the Arctic seas. More than 250 million years ago, he wrote, today's continents formed a single, vast landmass that he called Pangea (Ancient Greek for "the whole earth"). Around this supercontinent was a super ocean, Panthalassa ("all sea").

The evidence to support this shocking argument came – unusually, in that era of strict specialization – from everywhere: geology, geophysics, biology, paleontology, paleoclimatology, and beyond. This oft-denounced multidisciplinary strategy was crucial to Wegener's discovery. "Only by combining the information provided by all of the Earth sciences," he wrote, "can we hope to find out the 'truth' here."

Wegener found some of the strongest support for continental drift – which he actually called continental displacement – in the striking resemblance of many rock formations now separated by oceans. “It's as if we were to reposition the torn pieces of a newspaper by matching the edges and then checking that the printed lines run smoothly,” he wrote. On the biological side, he was impressed by the resemblance of not only marsupials but the parasites they infect, both in Australia and South America.


(Source: Public Domain / Wikimedia Commons)

He knew he had collected only circumstantial evidence, Lisa Yount writes in the biography: Alfred Wegener: Creator of the Continental Drift TheoryYet "he believed that the amount and variety of his evidence was so great that it amounted to evidence."

& # 39; Utter, damn rotten & # 39;

The geologists of the world emphatically disagreed. After a few overlooked editions and an English translation, Wegener & # 39; s book caused an intellectual storm in the 1920s. Austrian paleoclimatologist Fritz Kerner von Marilaun spoke of Wegener's "frenzied ravings," while British geologist Philip Lake said at a meeting of the Royal Geographical Society that Wegener "was not looking for truth, he pleads for a cause and is blind to any. fact that goes against it. "

The Americans – who had been at war with Wegener's homeland just a few years earlier – were particularly hostile. A decent summary of their response came from William Berryman Scott, president of the American Philosophical Society, who bluntly "utterly, damn rotten" the theory. stated.

At a 1926 conference in New York City to discuss continental drift, the leading experts attacked all the evidence. Many of their criticisms have been valid – especially with regard to the inconclusive suggestion that the mechanism for drift could be either the centrifugal force of the Earth's rotation or the pull of the tides on the Earth's crust – but, Yount writes, & They should not have been enough to make Earth scientists completely reject Wegener's theory. "

Read more: The Next Pangea: What Earth's Future Supercontinent Will Look Like

Nonetheless, they did, and their ridicule deters most would-be pursuers from continental drift. It is plain to see what was at stake for these men – the theory undermined the foundation of a science to which they had dedicated their lives. "If we are to believe Wegener's hypothesis," wrote Rollin Chamberlin, a leading geologist at the University of Chicago, "we must forget all that has been learned over the past 70 years and start all over again."

But even in the controversy of those early days, the first traces of acceptance were visible. "We are discussing this hypothesis because we want him to be right," said George William Lamplugh at the Royal Geographical Society meeting, noting that it would solve many long-standing problems for geology. "The underlying idea could pay off even better."

But that fruit needed advocates brave enough to cultivate it, and they were scarce. As British geologist Richard Dixon Oldham put it at the time, "it was more than any man who appreciated his reputation for scientific common sense, something like this theory should defend."


Wegener (left) and Rasmus Villumsen in Greenland, 1930. (Credit: Public Domain / Wikimedia Commons)

Death and recognition

Maybe Wegener wasn't concerned about his reputation. Perhaps he was confident that posterity would restore it. Regardless, he continued to search, answering the barrage of criticism and disapproval with increasingly sophisticated evidence. But by 1929, when he published the fourth and final edition of his book, it was still suffering a fatal flaw: As compelling as its wild mix of evidence was, it couldn't explain what moved the Earth's crust.

The following year, Wegener embarked on his latest adventure: a weather exploration expedition on Greenland's remote, barren ice sheet. He spent the summer and fall hauling supplies by dog ​​sled to the research station, 400 kilometers inland, but as winter approached, the locals abandoned him. With a band reduced to just two men, he was the last to provide just enough food and fuel to keep the station's crew alive until spring. On November 1, 1930, he left for the coast. The temperature had dropped below -60 degrees Fahrenheit.

On the way he died, probably of a heart attack. Months later, when a seeker found his body, a member reported that his face was "relaxed, peaceful, almost smiling" seemed. Wegener was honored as a great meteorologist and polar explorer – not as the architect of a great geological theory.

On that front, it would take another three decades for the world to catch up. As late as 1958, a book rejecting continental drift contained a foreword by Albert Einstein. Then, suddenly, in one of the great & # 39; I told you so & # 39; moments of science, the discoveries of seafloor spreading and the constant rumbling and crunching of colossal tectonic plates finally drove continental drift the main stream.

Wegener has not done everything right. It is not the continents that necessarily drift, but rather the plates of crust, or lithosphere, to which they are attached. And the force that drives this drift is not centrifugal or tidal, but convective – the Earth's inner heat keeps these plates moving. But this plate tectonics theory, one of the great revolutions in modern science, owes its existence to Wegener & # 39; s own creative theory and his willingness to imagine beyond the bounds of accepted wisdom. Continental drift, writes British geologist Anthony Hallam, "Stands not only as a precursor to the concept now prevailing, but also as its true ancestor."


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